ABSTRACT We sought to evaluate the hypothesis that mental health impairment in underweight women, where this occurs, is due to an association between low body weight and elevated levels of body dissatisfaction and/or eating-disordered behaviour.
Subgroups of underweight and normal-weight women recruited from a large, general population sample were compared on measures of body dissatisfaction, eating-disordered behaviour and mental health.
Underweight women had significantly greater impairment in mental health than normal-weight women, even after controlling for between-group differences in demographic characteristics and physical health. However, there was no evidence that higher levels of body dissatisfaction or eating-disordered behaviour accounted for this difference. Rather, underweight women had significantly lower levels of body dissatisfaction and eating-disordered behaviour than normal-weight women.
The findings suggest that mental health impairment in underweight women, where this occurs, is unlikely to be due to higher levels of body dissatisfaction or eating-disordered behaviour. Rather, lower levels of body dissatisfaction and eating-disordered behaviour among underweight women may counterbalance, to some extent, impairment due to other factors.

physical health and chronic medical conditions, is takeninto account in the analysis [5,6,8,21,24].In any case, the observation that mental health may beimpaired in underweight women would seem to present aparadox. That is, if it is accepted that impairment inwomen’s mental health associated with obesity is due pri-marily to the effects of body dissatisfaction and/or eating-disordered behaviour, then it would seem reasonable tohypothesise that low body weight would tend to be asso-ciated with better mental health [25,26]. An ego-syntoniceffect of low body weight in women - and the fact such aneffect would not be expected in men - might help toexplain why mental health impairment has been observedin underweight men - but not women - in some studies[1,16,27]. On the other hand, a tendency for underweightwomen to have lower levels of body dissatisfaction anddisordered eating might be counter-balanced by the pre-sence of a sub-group of underweight women with veryhigh levels of body dissatisfaction and eating disordersymptoms, namely, those with anorexia nervosa orvariants of this disorder not meeting formal diagnosticcriteria [28].A reading of the literature indicates that an overrepre-sentation of individuals with high levels of body dissatis-faction and/or eating-disordered behaviour is, in fact, thefavoured explanation for the finding of mental healthimpairment in underweight women. Thus, Ali & Lind-strom [22] noted that body image distortion seems to beassociated with underweight among young women in theindustrialised world and that “anorexia and bulimia maybe considered as the most severe and ultimate causes ofunderweight among young women” (p.324). Similarly,Ford and colleagues [9] noted that low BMI may be signif-icantly associated with female gender and, in turn, greaterweight loss goals when dieting and that lean individualsare likely to be a heterogeneous group that includes“healthy persons who exercise a lot, persons with eatingdisorders and clinically or subclinically sick persons”(p.26). The putative association between low body weightand body dissatisfaction/eating-disordered behaviour hasbeen invoked as an explanation of the association betweenlow body weight and mental health impairment in at leastfour other studies in which such an association has beenobserved [3,14,21,23] as well as in research conducted inother fields [26].Importantly, however, measures of body dissatisfactionand/or eating disorder psychopathology were not includedin any of these studies. Hence, the hypothesised associa-tions between body weight, body dissatisfaction/eating-disordered behaviour and mental health impairment couldnot be tested. To our knowledge, only one epidemiologicalstudy has included some assessment of body dissatisfac-tion and/or eating-disordered behaviour, in addition tobody weight and mental health. In a community sample ofwomen aged 18 to 25 years, Becker et al [21] found thatthe lifetime prevalence of any mental disorder was higherin underweight women than in normal-weight women,even after individuals with a lifetime diagnosis of anorexiaor bulimia nervosa were excluded from the underweightgroup. However, findings from this study are difficult tointerpret because the assessment of both eating disordersand other mental health problems was confined to thepresence or absence of disorders meeting formal diagnos-tic criteria [29,30], the number of participants meetingthese criteria was small and there was no assessment ofbody dissatisfaction.In sum, there appears to be little direct evidence tosupport - or refute - the popular notion that underweightis associated with elevated levels of body dissatisfactionand/or eating disordered behaviour in women or thatsuch an association accounts for mental health impair-ment. With this in mind, the goals of the present studywere as follows. First, we sought to confirm that mentalhealth is in fact impaired in underweight women, whencompared with normal-weight women. Second, we testedthe hypothesis that body dissatisfaction and/or eating dis-ordered behaviour are greater in underweight womenthan in normal-weight women. If both of these condi-tions held, then it would be possible to test the additionalhypothesis that impairment in mental health amongunderweight women is accounted for by body dissatisfac-tion and/or eating-disordered behaviour.MethodsStudy design and participantsThe research was conducted as part of the Health andWell-Being of Female ACT Residents Study, an epidemio-logical study of disability associated with eating-disorderedbehaviour among young adult women [19,30-36]. Thestudy was carried out in the Australian Capital Territory(ACT) region of Australia, a highly urbanised region thatincludes the city of Canberra (population of 314,000 in2002). Young women were chosen because of the com-paratively high prevalence of body dissatisfaction and eat-ing-disordered behaviour in this population [37]. Allaspects of the study design and methods were approved bythe ACT Human Research Ethics Committee.A detailed account of the study methods can be found inseveral previous publications [19,30-36]. In brief, self-report questionnaires were initially completed by 5,255female ACT residents aged 18 to 42 years. The question-naire included measures of eating-disordered behaviour(including items assessing body dissatisfaction), health-related quality of life, subjective quality of life, general psy-chological distress, physical activity and demographicinformation. Demographic variables assessed included: agein years; country of birth (Australia, not Australia); firstlanguage (English, not English); marital status (married,Mond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 2 of 10

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not married); parity (no children, one or more children);main activity (employed full-time, not employed full-time);educational attainment (bachelor’s degree or higher quali-fication completed/not completed); and possession of (pri-vate) health insurance (no, yes). Body mass index (BMI)(kg/m2) was calculated from self-reported height andweight [38].The sample comprised approximately 10% of the totalpopulation of young adult women in the ACT and wasrepresentative of this population in terms of socio-demo-graphic characteristics [34]. Thus, most participants wereborn in Australia (85.3%), had English as their firstlanguage (91.8%) and had completed 12 or more years offormal education (90.5%). Fifty-five per cent of participantswere married or living as married, 43.8% had one or morechildren, 62.8% were employed full- or part-time, 15.6%were full-time students and 17.5% nominated home dutiesas their main activity.The mean (SD) age of participants was 30.3 (7.2) years.The mean (SD) (BMI) among the 4,892 (93.1%) partici-pants who provided details of both height and weight was24.5 (5.3) kg/m2. Reflecting the study aims, participants inthe present study were the 231 women (4.7%) who wereunderweight (BMI < 18.5) and 2,976 women (60.8%) whowere normal-weight (18.5 ≥ BMI < 25.0) according to theconventional classification [39]. Findings relating to theassociations between obesity, eating-disordered behaviourand mental health have been reported elsewhere[19,30,36].Study measuresBody dissatisfaction and eating disordered behaviourEating-disordered behaviour was assessed using the EatingDisorder Examination Questionnaire (EDE-Q) [40], awidely-used, 36-item, self-report measure that focuses onthe occurrence and frequency of key eating disorder atti-tudes and behaviours during the past 28 days. Subscalescores - relating to dietary intake/restraint, concerns abouteating and concerns about weight or shape - and a globalscore, are derived from 22 items addressing attitudinal fea-tures [34]. Scores on each (item and) scale range from 0 to6, with higher scores indicating higher symptom levels.Remaining items of the EDE-Q assess the occurrence andfrequency of specific eating disorder behaviours, namely,binge eating, self-induced vomiting, misuse of laxatives ordiuretics, extreme dietary restriction and excessive exer-cise. These items do not contribute to subscale scores.Two of the EDE-Q (Weight/Shape Concerns subscale)items specifically address body dissatisfaction, namely,“How dissatisfied have you felt about your weight” and“How dissatisfied have you felt about your shape”. Theaverage of scores on these 2 items, which were highlycorrelated (r = 0.89), was used as a measure of body dis-satisfaction in the present study [41].Whereas the EDE-Q global score provided a continuousmeasure of eating disorder psychopathology, eating disor-der “cases” were identified using an operational definitioninformed by our previous research, namely, the occurrenceof extreme weight or shape concerns in conjunction anyregular eating disorder behaviour [38,30]. For binge eating,self-induced vomiting, and purging behaviours, “regular”was defined as “at least weekly”, whereas regular extremedietary restriction and excessive exercise were recognisedif these behaviours occurred, on average, 3 or more timesper week [34]. Although, in the absence of interviewassessment, participants meeting these criteria should beviewed as “probable” rather than “true” cases, the criteriahave been found to identify individuals with high levels ofeating disorder psychopathology and functional impair-ment [38,30].Mental healthHealth-related quality of lifeHealth-related quality of life was assessed with the MedicalOutcomes Study (12-item) Short-Form disability scale (SF-12) [42]. Items of the SF-12 are summarised into twoweighted scales (Physical Component Summary scale,PCS; Mental Component Summary scale, MCS), designedto assess physical and mental health impairment. Eachscale is scored to have a mean of 50 and standard devia-tion of 10 (in the US population), with lower scores indi-cating higher levels of impairment. The SF-12 has verygood psychometric properties, including demonstratedvalidity in the Australian population [42,43]. PCS itemsinclude “Does your health now limit you in moderateactivities, such as moving a table, vacuuming or playinggolf?” and “During the past four weeks, were you limitedin the kind or work or other activities undertaken as aresult of your physical health?”, whereas MCS itemsinclude “During the past four weeks have you accom-plished less than you would like as a result of any emo-tional problems?” and “During the past four weeks howmuch of the time have you felt calm and peaceful"? In thepresent study, the SF-12 MCS was the outcome of interestwhereas physical health, as assessed by the SF-12 PCS, wasincluded as a covariate. Cronbach’s alpha was 0.82 for thetotal scale and 0.80 for the 6 items comprising the MCS.Subjective quality of lifeSubjective quality of life was assessed using the WorldHealth Organization Brief Quality of Life AssessmentScale (WHOQOL-BREF) [44,45], a 26-item measure yield-ing scores on each of four domains relating to the indivi-dual’s subjective evaluation of their physical health,environmental health, psychological health and social rela-tionships. Items are scored on a five-point, Likert-typescale, with scores of ‘’1’’ and “5” indicating, respectively,extreme dissatisfaction and extreme satisfaction. Only thePsychological Functioning (QOL-P) subscale, which canMond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 3 of 10

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be viewed as a measure of perceived satisfaction with keyaspects of emotional well-being, was considered in thepresent study. Items of the QoL-P include “To what extentdo you feel your life to be meaningful"? and “How satisfiedare you with yourself?’ One of the (6) items comprisingthe QOL-P, which addresses satisfaction with “bodilyappearance”, was excluded when calculating the scalescore. Cronbach alphas for the 5- and 6-item scales were,respectively, 0.80 and 0.81.General psychological distressGeneral psychological distress was assessed with theKessler Psychological Distress Scale (K-10), a 10-itemself-report measure designed for use in general popula-tion surveys [46]. In Australia it is also used as an out-come measure among individuals treated within mentalhealth services [47]. The frequency (during the past fourweeks) of each of 10 symptoms - relating to anxiety anddepressive mood - is measured on a scale from one tofive, such that total scores range from 10 to 50 withlower scores indicating higher symptom levels. This cod-ing method was employed - i.e. in preference to an alter-native method in which lower scores indicate lowersymptoms levels [47] - so that lower scores would indi-cate poorer mental health for all 3 mental health mea-sures. Findings from the Australian National Survey ofMental Health and Well-Being suggested that individualsscoring in the extreme range (≤ 30) have a high probabil-ity of meeting diagnostic criteria for an anxiety or affec-tive disorder according to interview assessment [47].Cronbach’s alpha in present study was 0.91.Physical activityIn addition to the questions assessing the use of exerciseas a means of weight control (included in the EDE-Q),three questions were included that assessed the fre-quency of mild, moderate and hard exercise during thepast four weeks [35]. Based on these questions, a dichot-omous variable was created such that participants whoreported any of the three forms of exercise on averageat least 3 times per week during the past four weekswere considered to be regular exercisers.Statistical analysisLoess curves were used to examine the associationsbetween BMI, as a continuous variable, and each measureof mental health - SF-12 MCS, QOL-P and K-10 - in thetotal sample (n = 4,892). Loess, which stands for locallyweighted scatterplot smoothing, is a method for fitting acurve to a scatter plot that provides a graphical represen-tation of the relationship between two variables withoutmaking any a priori assumptions about the form of thatrelationship [48].Independent-samples t-tests were used to comparescores on continuous variables, namely, age, BMI, bodydissatisfaction, EDE-Q subscale scores and scores on theSF-12 PCS and MCS, QOL-P and K-10, betweenunderweight and normal weight participants, whereas chi-square tests were used to compare groups on categoricaloutcomes, namely, demographic characteristics, the occur-rence of specific eating disorder behaviours, the occur-rence of regular physical activity and the prevalence ofprobable eating disorder cases. Bivariate correlations werecalculated using the Pearson correlation coefficient. Linearregression models [49] were used to test the hypothesisthat impairment in mental health associated withlow body weight, where this was observed, was accountedfor by body dissatisfaction and/or eating-disorderedbehaviour.A significance level of 0.05 was employed for all tests, alltests were two-tailed and all analysis was conducted usingSPSS version 17.0. For analyses involving the SF-12, boththe standard scoring method, employing factor scoresderived by means of orthogonal rotation, and an alterna-tive method, employing factor scores derived by means ofoblique rotation, were employed [50]. Since the main find-ings were unchanged, only findings based on the standardscoring method are reported.ResultsFigures 1, 2, and 3 show Loess curves of the relation-ships between BMI and scores on the SF-12 MCS,QOL-P, and K-10, respectively. As can be seen, bothvery low and very high body weights were associatedwith mental health impairment and this was the case forall 3 measures.As would be expected, moderate to high positive cor-relations were observed between the different measuresFigure 1 Loess curve showing the association between bodymass index (BMI) (kg/m2) and mental health functioning, asmeasured by the Medical Outcomes Study Short Form MentalComponent Summary Scale (SF-12 MCS), in the total sample (n= 4,892) (Note: lower scores on the SF-12 MCS indicate greatermental health impairment).Mond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 4 of 10

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of mental health (MCS, QOL-P: 0.71; QOL-P, K-10:0.72; MCS, K-10: 0.76). Further, body dissatisfaction washighly correlated with overall levels of eating disorderpsychopathology as measured by the EDE-Q Globalscore (r = 0.82).Underweight women were less likely to be married(24.2% vs 37.2%; × = 15.51, p < 0.01), less likely to haveone or more children (30.1% vs 39.9%; × = 8.52.5, p <0.01), less likely to have completed tertiary studies(29.5% vs 41.7%; × = 12.95, p < 0.01) and less likely tohave private health insurance (50.5% vs 60.1%; × = 7.14,p < 0.01) than normal weight-women, whereas thegroups did not differ with respect to employment, coun-try of birth or first language (all p > 0.05).Comparisons between underweight and normal-weight participants on continuous variables are shownin Table 1. As can be seen, underweight women wereyounger and had lower scores (indicating higher levelsof impairment) on the SF-12 PCS and on all 3 mea-sures of mental health, than normal-weight women,although differences on the SF-12 MCS did not reachstatistical significance. It is also apparent that under-weight women had lower levels of body dissatisfactionand lower scores on each of the EDE-Q subscales thannormal-weight women.There were no differences between groups withrespect to the occurrence of eating disorder behaviours(all p > 0.05), nor with respect to the prevalence ofprobable eating disorder cases (underweight: 3.5%; nor-mal-weight: 5.8%; × = 2.27, p = 0.13). However, under-weight women were less likely to be regular exercisersthan normal-weight women (47.7% vs 56.6%; × = 5.25,p < 0.05).Since underweight was associated with lower, ratherthan higher, levels of body dissatisfaction and eating dis-order psychopathology, there was no basis on which toproceed with formal tests of the hypothesis of media-tion. Post-hoc analysis was conducted, however, in orderto determine which variables (other than body dissatis-faction and eating-disordered behaviour) might haveaccounted for the observed association between lowbody weight and mental health impairment and to eluci-date the comparative importance of different variables inaccounting for mental health impairment among under-weight participants.For the first analysis, hierarchical linear regression wasused to determine if differences between groups in men-tal health impairment remained after controlling forpotential covariates, namely, those variables that differedbetween groups in bivariate analysis. A dichotomousvariable indicating weight status (underweight, normal-weight) was used in place of BMI for this analysis. Asimilar method was employed for the second analysis,except that all variables were entered simultaneously,body dissatisfaction and eating-disordered behaviour (asmeasured by the EDE-Q global score) were includedand weight status was replaced with BMI.Results of the first analysis are summarised in Table 2.As can be seen, the association between weight statusand scores on the K-10 remained significant (p = 0.04)after controlling for demographic variables andapproached significance (p = 0.07) after physical healthand physical activity were added to the model. For theQOL-P, by contrast, the inclusion of demographicFigure 2 Loess curve showing the association between bodymass index (BMI) (kg/m2) and subjective mental health, asmeasured by the WHOQOL-BREF Psychological Health subscale(QOL-P), in the total sample (n = 4,892) (Note: lower scores onthe QOL-P indicate greater mental health impairment).Figure 3 Loess curve showing the association between bodymass index (BMI) (kg/m2) and general psychological distress,as measured by the Kessler Psychological Distress Scale (K-10)in the total sample (n = 4,892) (Note: lower scores on the K-10indicate greater mental health impairment).Mond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 5 of 10

Study implicationsThe primary implication of the present study is that men-tal health impairment in underweight women, where thisoccurs, is unlikely to be accounted for by an associationbetween low body weight and elevated levels of body dis-satisfaction or eating-disordered behaviour. Rather, bodydissatisfaction and eating disordered behaviour appear tobe comparatively uncommon among underweight women.Interestingly, however, body dissatisfaction was stillstrongly predictive of poor mental health in multivariableanalysis conducted within the underweight group. Takentogether, these findings suggest not only that higher levelsof body dissatisfaction or eating-disordered behaviouramong underweight women do not account for mentalhealth impairment, but also that lower levels of body dis-satisfaction and/or eating disordered behaviour amongunderweight women may counterbalance, to some extent,mental health impairment due to other factors.Consistent with findings from other recent epidemiolo-gical studies [7,14], the prevalence of underweight was lowamong women in the present study, less than 5%. Givencurrent concern surrounding the high prevalence of obe-sity in industrialised nations, research addressing theimpact of underweight on mental health has not been apriority. Indeed, underweight individuals have often beenexcluded in studies of the association between body weightand mental health due to concerns that high levels ofimpairment among underweight individuals might compli-cate interpretation of comparisons between obese andnon-obese individuals [3,5]. Similar concerns have arisenin research addressing the association between obesity andmortality [24]. However, it is important to critically evalu-ate the validity of anecdotal evidence, particularly whenthere are implications for public health practice. For exam-ple, Ali & Lindstrom [22] noted that interventions toimprove psychological health in underweight womenwould need to deal with the body norms/image messagesdisseminated in the popular media. The present findingsargue against this view. The findings do suggest, however,that women who are very underweight - like those whoare very overweight - are a vulnerable group, being atincreased risk of impairment in both physical and mentalhealth.We can only speculate as to why the notion that lowbody weight is associated with body dissatisfaction and/oreating-disordered behaviour is so widely accepted whenthere is so little evidence to support it. There may be poorunderstanding of the epidemiology of eating-disorderedbehaviour among researchers not familiar with this litera-ture, for example, low awareness of the fact that eating dis-orders characterised by normal or above-average bodyweight far outnumber those characterised by low bodyweight [29]. There may also be a tendency for publichealth researchers to generalise from the clinical/hospitalsetting, in which individuals presenting with the combina-tion of low body weight and extreme concerns aboutweight or shape are more conspicuous [51]. In any case,our findings suggest that there is a need to address themisconception that low body weight is associated withbody dissatisfaction and/or eating-disordered behaviour inunselected samples.Study limitations and other methodologicalconsiderationsSeveral limitations of the present study should be noted.First, some potentially important covariates were notassessed. In particular, there was no assessment ofsmoking or of chronic medical conditions, both ofwhich may be associated with low body weight and/ormental health impairment [6,7,22,24]. The higher levelsTable 3 Multiple linear regression analysis of variables associated with each measure of mental health (SF-12 MCS,QOL-P and K-10) among underweight women (n = 231)SF-12 MCSbAge.017BMI-.070Marital status.102Parity-.016Employment-.103Education-.063Country of birth.013First language.083Health insurance.064Physical health-.127Physical activity.070Body dissatisfaction-.400Eating disorder psychopathology-.023QOL-Pb-.011-.076.016-.019-.030.024-.095.208.098.179.085-.513.039K-10b-.019-.094.052.060-.083.004-.056.151.153.086.016-.478.077Covariatesppp.872.344.245.872.197.454.886.361.387.082.376.000.817.912.289.855.842.695.770.266.018.167.011.271.000.683.856.206.552.548.300.958.529.097.040.229.844.000.445Mond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 7 of 10

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of mental health impairment observed in underweightwomen might also have been due to the presence of asmall number of individuals with very high symptomlevels, namely, those with anxiety, affective, substanceuse or other mental disorders [6,7]. Interview assess-ment would be required to test this hypothesis. Ourgoal was to test the hypothesis that body dissatisfaction/eating-disordered behaviour mediates the associationbetween low body weight and mental health impair-ment, rather than to examine factors associated withimpairment.Second, approximately 40% of individuals approachedto participate in the study chose not to return a com-pleted questionnaire and individuals with anorexia orvariants of anorexia may be over-represented in thissubgroup [52]. To the extent that a bias of this kindoccurred, both the extent of mental health impairmentin the underweight group and the role of body dissatis-faction/eating disorder psychopathology in accountingfor this impairment may have been underestimated.Individuals with other mental disorders may also havebeen over-represented among non-respondents [53].However, these observations do not change the factthat, in the present study, greater mental health impair-ment was observed among underweight women despitethese women having lower levels of body dissatisfactionand eating disorder psychopathology than normal-weight women.Third, the present findings necessarily apply to under-weight defined as a BMI of < 18.5 kg/m2. Although thiscriterion is widely accepted, it is nevertheless arbitraryand different findings may have been observed had amore or less stringent operation definition of low bodyweight been employed [1,22]. In addition, BMI was cal-culated based on self-reported height and weight in thepresent study. However, we found very good agreementbetween BMI based on self-reported height and weightand BMI derived from actual (measured) height andweight in pilot work [38].Fourth, the present findings necessarily apply toyounger women from an urbanised, affluent region. Thispopulation was appropriate for an initial study becausethe hypothesis that impairment in mental health asso-ciated with low body weight is due to body dissatisfactionand/or eating-disordered behaviour has been proposedprimarily in relation to young women from industrialisednations [22,26]. As suggested previously, it may makemore sense to consider the role of body dissatisfaction inrelation to mental health impairment in underweightmen, given that underweight males are more likely to bedissatisfied with their bodies than normal-weight malesand given that the prevalence of body dissatisfaction andits impact on mental health may be increasing in males[1,20,27,54].Some comment is warranted concerning the treat-ment of body dissatisfaction and eating-disorderedbehaviour as distinct constructs. The key distinctionbetween individuals with extreme weight or shape con-cerns and individuals with eating disorders is the regu-lar occurrence of one or more eating disorder (i.e.binge eating or extreme weight-control) behaviours.Since extreme weight or shape concerns in the absenceof eating disorder behaviours are more common thanthe combination of concerns and behaviours, it is notsurprising that body dissatisfaction emerged as thestronger predictor of impairment among underweightparticipants. But it needs to be remembered that thereis extensive overlap between these constructs in gen-eral population samples [41].Finally, since this was a cross-sectional study, theusual caveats concerning the direction of any observedassociations apply [4,55]. The available evidence fromlongitudinal studies suggests that associations betweenbody dissatisfaction/eating disordered behaviour andmental health impairment are likely to be bidirectional[56-58]. Notable strengths of the present research werethe recruitment of a large, general population sample ofwomen, comprehensive assessment of eating-disorderedbehaviour and the inclusion of three different measuresof mental health.ConclusionsTo conclude, the findings of the present study suggestthat mental health impairment in underweight women,where this occurs, is unlikely to be due to higher levelsof body dissatisfaction or eating-disordered behaviour.Rather, lower levels of body dissatisfaction and eating-disordered behaviour among underweight women maycounterbalance, to some extent, impairment due toother factors. The findings also suggest that womenwho are very underweight are a vulnerable group, beingat increased risk of impairment in both physical andmental health.Ethics approvalThe research was conducted with the approval of theACT Human Research Ethics Committee.AcknowledgementsThe Health and Well-Being of Female ACT Residents Study was funded byThe Canberra Hospital Private Practice Fund, ACT Health and CommunityCare and ACT Mental Health. Dr Mond is supported by a National Healthand Medical Research Council Sidney Sax Fellowship.Author details1School of Sociology, Australian National University, Canberra, Australia.2Australian Demographic & Social Research Institute, Australian NationalUniversity, Canberra, Australia.3School of Medicine, University of WesternSydney, Campbelltown, Australia.4Rural Clinical School, Medical School,Australian National University, Canberra, Australia.Mond et al. BMC Public Health 2011, 11:547http://www.biomedcentral.com/1471-2458/11/547Page 8 of 10

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[Show abstract][Hide abstract]ABSTRACT:
Underweight is associated with increased risk of mortality and morbidity. It is reported that the prevalence of underweight is increasing among Korean young women. However, there have been few studies on sociodemographic factors related to being underweight. This study was conducted to elucidate the sociodemographic characteristics of Korean underweight adults.
This study is a cross-sectional study of 7,776 adults aged 25 to 69 years using data from the Korea National Health and Nutrition Examination Survey, 2007-2010. Study subjects were composed of underweight and normal-weight adults excluding overweight adults. Body mass index was calculated from measured height and weight. Health behaviors such as smoking, drinking, and physical activity were surveyed through self-administered questionnaires, and socioeconomic status, marital status, and history of morbidity were surveyed through face-to-face interviews.
Women had a higher frequency of underweight (10.4% vs. 7.0%, P < 0.001) than men. Among men, current smoking (odds ratio [OR], 1.62) and past history of cancer (OR, 2.55) were independently related to underweight. Among women, young age (OR, 2.06), former smoking (OR, 1.69), and being unmarried (OR, 1.56) were identified as independently related factors of underweight. In addition, among both men and women, alcohol drinking (men OR, 0.57; women OR, 0.77) and past history of chronic diseases (men OR, 0.55; women OR, 0.43) were independently related to a lower frequency of underweight.
We showed that various sociodemographic factors were associated with underweight. It was ascertained that there were differences in the sociodemographic factors related to underweight between Korean men and women.

[Show abstract][Hide abstract]ABSTRACT:
Underweight refers to the weight range in which health risk can increase, since the weight is lower than a healthy weight. Negative attitudes towards obesity and socio-cultural preference for thinness could induce even underweight persons to attempt weight control. This study was conducted to investigate factors related to weight control attempts in underweight Korean adults.
This was a cross-sectional study on 690 underweight adults aged 25 to 69 years using data from the Korea National Health and Nutrition Examination Survey, 2007-2010. Body image perception, weight control attempts during the past one year, various health behaviors, history of chronic diseases, and socioeconomic status were surveyed.
Underweight women had a higher rate of weight control attempts than underweight men (25.4% vs. 8.1%, P < 0.001). Among underweight men, subjects with the highest physical activity level (odds ratio [OR], 7.75), subjects with physician-diagnosed history of chronic diseases (OR, 7.70), and subjects with non-manual jobs or other jobs (OR, 6.22; 12.39 with reference to manual workers) had a higher likelihood of weight control attempts. Among underweight women, subjects who did not perceive themselves as thin (OR, 4.71), subjects with the highest household income level (OR, 2.61), and unmarried subjects (OR, 2.08) had a higher likelihood of weight control attempts.
This study shows that numbers of underweight Korean adults have tried to control weight, especially women. Seeing that there are gender differences in factors related to weight control attempts in underweight adults, gender should be considered in helping underweight adults to maintain a healthy weight.

[Show abstract][Hide abstract]ABSTRACT:
Objective
We examined the relative importance of physical health status, weight/shape concerns, and binge eating as mediators of the association between obesity and psychosocial impairment in a community sample of women and men.Method
Self-report measures of eating disorder features, perceived physical health and psychosocial functioning were completed by a general population sample of women and men classified as obese or non-obese (women: obese=276, non-obese=1220; men: obese=169, non-obese=769). Moderated mediation analysis was used to assess the relative importance of each of the putative mediators in accounting for observed associations between obesity and each outcome measure and possible moderation of these effects by sex.ResultsWeight/shape concerns and physical health were equally strong mediators of the association between obesity and psychosocial impairment. This was the case for both men and women and for each of three measures of psychosocial functioning - general psychological distress, life satisfaction and social support - employed. The effects of binge eating were modest and reached statistical significance only for the life satisfaction measure in men.ConclusionA greater focus on body acceptance may be indicated in obesity prevention and weight-management programs.International Journal of Obesity accepted article preview online, 11 June 2014; doi:10.1038/ijo.2014.100.